Stair treads installation and humidity

[Nick]

..................and I live on the coast.

Not sure I'm understanding this. Plywood? The risers will be the only plywood on the stringers, the treads are 1 inch unfinished oak. The floor inside the stair enclosure pins out at 12% 14% and 16%, the treads are stored elsewhere and pin out at 6% or less.
Plan is to acclimate the treads in the house bu leaning them against the walls for good air circulation. I was told a week or possibly two to acclimate.

I figure sealing the floor inside the stairwell with something.......... Bosticks, or Aquabar and plywood, to stop air from coming in from under the house.
Once the stairwell is sealed off by installing treads and risers, there will be no air movement inside the cavity.
If the floor under the stairs is not sealed off, the moisture will in my opinion, build up under the stairs once they are finished.
I'm gonna seal the underside of all the treads after it's acclimated.

You won't know till you pin it .

 

[highup]

........suggesting I won't?

I didn't pin the stringers. (not yet) More concerned about how much moist air is traveling up through the floor from under the house, waiting to be held captive inside the stairwell once its sealed up with risers.

 

[Ernesto]

..................and I live on the coast.

The floor inside the stair enclosure pins out at 12% 14% and 16%, the treads are stored elsewhere and pin out at 6% or less.
.

The oaks stair treads have been upstairs in the heated garage for many months now. They are separated by cardboard strips to provide air circulation.
It stays about 70 degrees with 54% humidity.
What's going to happen when the treads get installed in the house?

You say the treads pin out at 6% yet they are stored at 70f @ 54% rh? Your meter is jacked, red oak should pin out at around 9 to 10% @ that temp and rh.

Your fir is pinning at 11 to 12 % ? Check this graph.

 

[highup]

You say the treads pin out at 6% yet they are stored at 70f @ 54% rh? Your meter is jacked, red oak should pin out at around 9 to 10% @ that temp and rh.

Your fir is pinning at 11 to 12 % ? Check this graph.

How do you check the end of the board if it's nailed to the floor?

I pinned the top side of the floor and the treads to get my readings.
I used the short pins.

 

[Ernesto]

How do you check the end of the board if it's nailed to the floor?

I pinned the top side of the floor and the treads to get my readings.
I used the short pins.

Why are you pinning the ends of the boards? Pin in the middle, with the grain with longer pins if possible. Pinning on ends of wood is like pinning across the grain which will give you a false reading.
Don't worry about the holes, they can be filled.Or pin the treads from underneath.

Besides all that if your treads have been acclimated to that temp and rh which after looking at a zone chart of your location, those readings are normal.

To get a reading of 6% for red oak you'd have to be at like 25 to 30% rh or.... living in New Mexico or Arid-zona. lol

 

[Ernesto]

Here's a cool document from The Teachers Hand-Book of Slojd you may appreciate. Print date 1892. You can copy it online as there is no copyright.

 

[Ernesto]

What meter are you using....

 

[highup]

What meter are you using....

...........absorbing the info on the graphs. Much appreciated.

It's just a Ligno mini. I have a friend that allso has one and the readings he gets are same as mine. Hate to think they are both off................ and by the same amount.
Also, I just pinned a half a dozen different woods, inside my place and out under the carport............... across the grain, or with the grain, same readings. (different on each board of course) I suppose if the meter read in tenths, the readings could change by a point.
The Mini has LED's which measure every 2% (6% 8% 10% etc.)
If two LEDs light up, it's in between the two readings.

 

[Floorist]

Just nail with gutter spikes, then they can't move.

 

[highup]

Just nail with gutter spikes, then they can't move.

'cmon hillbilly................ carriage bolts. It's a classy place.

 

[Ernesto]

...........absorbing the info on the graphs. Much appreciated.

It's just a Ligno mini. I have a friend that allso has one and the readings he gets are same as mine. Hate to think they are both off................ and by the same amount.
Also, I just pinned a half a dozen different woods, inside my place and out under the carport............... across the grain, or with the grain, same readings. (different on each board of course) I suppose if the meter read in tenths, the readings could change by a point.
The Mini has LED's which measure every 2% (6% 8% 10% etc.)
If two LEDs light up, it's in between the two readings.

I have one of those Ligno mini's. Get the SDM if you want a great meter. Oops, breakfast is calling.